Read the Docs provides the ability to write prose documentation that
links to referential or API documentation, including other projects
hosted in your organization, or open source projects hosted on
readthedocs.org.

reStructuredText support

Markdown support

Sphinx generated documentation

Supports linking to Python, Ruby, JavaScript, Java, and many more languages.

Continuous Documentation

Your documentation is rebuilt with each new commit to your
repository. We consider this Continuous Documentation. It
allows for process to be added to your development workflow to ensure
your documentation is consistently receiving the attention it deserves.

Documentation is hosted by each version or branch of your software,
so that your documentation always reflects the software you support.
Your documentation can now evolve alongside your software.

Pull from Github

Pull from Bitbucket

Supports Git, Mercurial, Subversion, and CVS

Documentation You'll Use

Great documentation exists at the intersection of collecting and
sharing information. Having the right tools can facilitate writing,
which is the first step to increasing the value of your documentation.
When you have documentation worth reading, it's still important to
have the correct tools to find and use what your wrote.

With all your documentation in one spot, information can link projects
together and everything is searchable and easily discoverable.